From one extreme event to another: heat domes and landslides.

Much of Europe has been dominated by a historic heat dome, leading to the falling of both daytime and nighttime temperature records. On August 23, for example, France shattered its all-time record as the town of Siran recorded 44.4°C. Numerous Swiss cities toppled records the following day, including in Geneva, which reached 39.3°C. In Greece, the on-going heat has fueled more wildfires, which have so far displaced more than 21,500 people. 

For many of those caught in the extreme heat, relief from the weakening of the blocking pattern in the jet stream that has maintained the heat dome has been short lived, as they are thrown into the grip of another extreme weather event. The now-faster jet stream combined with hotter-than-normal water temperatures in the Mediterranean Sea is a dangerous combination. Enhanced wind shear, unstable air masses, increased humidity and warm waters are prime conditions for supercells, which can yield strong tornadoes, thunderstorms, hail and damaging winds.  

On Sunday, the Spanish island of Mallorca (Majorca) was hit with a sudden thunderstorm, one of several in the Balearic Islands. Gusts exceeded 120kph/75mph. In some scary footage of the event, the Britannia, a P&O Cruises ship based out of Southampton, broke free of its tether and collided with a freighter. One British holiday-goer described the experience to the BBC as feeling like she “was in the Wizard of Oz.” 

This windstorm in Mallorca is amongst extremes throughout southern Europe, as torrential rain has led to landslides and flooding, affecting businesses, transportation and utilities in the area. In Germany, 150 houses were damaged from flooding in the Straubing region, and more than 100 residents in the Aichach-Friedberg region were evacuated and 12 were injured. In Graz, Austria, hail measuring 9cm was reported. Flash floods are especially concerning in areas in northern Italy, Austria, Slovenia and Switzerland, which were hit badly earlier this month with flooding and landslides. 

Did you know that the rapidly warming Arctic is one of the leading causes for blocking patterns to form in the jet stream, leading to both the heat dome and the extreme weather following its release? At its most basic, the jet stream maintains its speed through being sandwiched between cooler Arctic and warmer tropic air masses. When the Arctic heats up, the large air current can be disrupted and is prone to patterns that can lead to lingering heatwaves and unstable air masses. Learn more about the Arctic and global risks, such as extreme weather here.

These storms are expected to continue at least through Wednesday.  

Image credit: Dani Torres (@jumpcarey)